The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section. Situations arise in which it is useful for a user to be able to measure the actual size of an object of interest in a scene captured in an image. For example, in the healthcare context, it is often important to be able to know the actual size of a wound more accurately than a visual approximation of a user. One conventional technique involves including a measuring tool, such as a ruler, adjacent the wound site so that after the image is acquired, a user may manually estimate the size of the wound based upon the measurement markings on the ruler. One disadvantage of this approach is that it does not provide an accurate measurement of the wound because the user must visually estimate the size of the wound based upon the ruler located in proximity to the wound and not on the wound itself. Another disadvantage of this approach is that it relies upon the skill of the clinician, which may vary significantly across different personnel, providing inconsistent measurements.